Hydraulic duplicating mechanism for machine tools and the like



Feb. 2, 1960 DRI CH 2,923,518

M. GOO HYDRAULIC DUPLICATING MECHANISM FOR MACHINE TOOLS AND THE LIKEFiled Aug. 27. 1953 3 Sheets-Sheet 1 INVENTOR 1- My aaoax c/ BY w ZVh/ZwM /CMWM ATTORNEY Feb. 2, 1960 M. GOODRICH HYDRAULIC DUP LICATINGMECHANISM FOR MACHINE TOOLS AND THE LIKE Filed Aug. 27, 1953 3Sheets-Sheet 2 0 0 a 2 W u/ w 4 4 w v, A 3 x 7 0 0 47 a T. 5 2 6 I 6% /rfl c K r m u I II Il fl In H 0 M a 1 006 8241M a 2/ mnm 7 a Z7 4/ 7 2 8p w a U d St tes Pa m 0,

HYDRAULIC DUPLICATING MECHANISM FOR MACHINE TOOLS AND THE LIKE MaxGoodrich, Holt, Mich.

Application August 27, 1953, Serial No. 382,535

Claims. (CL251-3) The present invention relates to improvements inhydraulic duplicators attachable to such machine tools as verticalmills, boring mills, lathes, planers, shapers, and

the like for controlling the movement of the tool.

Devices of the type to which the present invention pertains are wellknown commercially and a great many noncommercial proposals pertainingto such devices ap-,

extremely fine work and which permits the practical manufacture of anattachment of high precision performance.

Thus, an object of the invention is to provide an improved hydraulictracer unit so designed that the sensitivity of the tracer finger to allchanges in contour of the master template, or the like, is transferredto the valve mechanism which controls the manipulating fluid in such amanner that the sensitivity of the tracer finger thus transferred isundiminished, unretarded and in direct proportion. 7

Another object is to provide novel structural arrangement in devices ofthe type described for obviating the tendency toward chatter in theperformance of extremely fine duplication.

2 Fig. 4 is an exploded perspective view of the sectional structure ofthe control valve,

Fig. 5 is a detail of the connection between the valve and stemstructure, t p

Fig. 6 is a view similar to Fig. S taken through'the ports of thedampening structure, V

Fig. 7 is atop view of Fig. 3, and v I Fig. 8 is a detail of thestructure for maintaining the valve chamber full of oil.. I i I,

As shown in Figs. 1 and 2, the duplicator attachment 10 is carried uponsuitable cross slide structure 12 attached to the vertically movablespindle structure of the milling machine 14 so as to follow themovement, of the tool 16. Adjustment of the attachment 10 in ahorizontal plane is providedto align the tracer finger 18 with the tool16 as well as withthe template 20 mounted on a bracket 22 to move withthe table 24 upon which the work 26 to be machined is carried. V

The carriage structure 28 of the attachment 10 comprises a lower splitbushing portion 30 in which the tracer stem housing 32 is vertically.slidable. A suitable at tachment bolt 34 having a handle 36 isprovided'for clamping the split sleeve30 upon the housing 32 followingvertical adjustment, As shown, the housing 32 has an extremely threadedsurface 38 to receive the adjustment nut 40 in position for rotationbetween the upper surface 42 of the sleeve 30 and the lower surface44 ofthe thrust plate 46 attached at 48 to the carrier 28. A surface of thenut-40 may. have graduations marked thereon to aid in the verticaladjustmentof the housing 32 upon manual rotation of the adjustment nut40.

Referring to Fig. 3, the tracer finger 18 is heldin the stem 52 by aclamp screw 54. With the finger 18 .out of contact with the template 20the stem 52 is vertically supported by the stem holder 56 which takesthe form of an externally threaded bushing screwed into Another objectof the invention is to provide a tracer the free movement of the Afurther object is' to provide a conveniently located-"' regulator foractuatingthe control valve. wherebyjthe operator may bring the tool intocontact with the, work with extreme care. These and other objects andadvantages of the present invention residing in the combination,construction and arrangement of the component parts will appear from thefollowing specification and the appended claims.

In the drawings,

Fig. 1 is a perspective view of a vertical milling mav chine equippedwith my improved duplicator attachment,

'Fig. 2 is a perspective view of the tracer and control valve unit shownin its mounting structure,

Fig. 3 is a vertical cross-sectional view of the trader and controlvalve unit shown in Fig. 2,

the internally threaded counterbored lower end 58 of the stem housing32. To remove all s1ack between this threaded connection,. a spring 60is inserted between the upper end of the stem holder 56 and the shoulder62; the spring 60 being sufiiciently strong as to prevent any sidemovement between the threaded connection when there is side pressure onthe tracer finger 18.

The stem 52 has a concentric slightlyenlarged cylindrical portion 64which is provided with an extremely close sliding fit within a narrowannular surface constituting what is-characterized herein as an annularfulcrum 66; in practice the clearance between the sliding partsconstituting the sliding fit being in the orderrof V 'of the cylindricalportion 64 is attached to engage to support the stem 52; the seatportion 68 being disposed 'at to a radial line between a point ofcontact between the edge 70 and the seat portion 68 and the point ofintersection of the longitudinal axis of the cylindrical portion 64 witha medial plane through the annular 'fulcrum 66. 60

The axial extent of that portion of the annular fulcrum 66which formsthe .0002" sliding fit with the cylindrical portion 64 is in the orderof 1A3". With this narrow bearing and with .0002" clearance, sidemovement inall directions may take place at, the lower, end of thetracer finger 18 to the order of A with the tracer finger of usuallength, namely, in the order of 3" to 5" below the fulcrum 66. With theseat portion 68 located and constructed as above described, only slightmovementof the edge 70 will take place on the seat 68 and such movementwill not produce any appreciable upward camrning movement to the stem52. Clearance is provided at 72 f between the lower end and the stern52tto accommoj'nut118 holds the socket 117 in position. V 'Iheadjustableconnection between the upper threaded end'pf the rod 116 andthe valvespool 120,'best shown Fig. ,5, comprises an internallythreaded' sleeve122 date the side movementfofthe finger 18 inall directions,

"The ster n 52 is extended a substantial distance above the fulcrum 66,preferably: a distance approximating the distance to: the lower end, ofthe finger18 to provide the up er end 74 and the annular ball, seat 76withapproxi- ,mately the sameamount ofside movement as may take place atthe lower end ofthe tracer finger 18..

. -To transfer both axial and lateral movement of the stem 52 to' thesectional valve shown in Fig. 3, a ball 78 rests upon the seat 76' andreacts against a similar annular. seat 80 defined in the" externallythreaded pin abutment member82 which is-also the i nner race of the ballgazette, a e

bearing. structure84; The outer race for the bearing 84 :takes thefor'ni pf a sleeve 86pressed intoa counter- ,hore at the upper end ofthe stern housing 32. Retainng rings 88 hold the bearings 84 positioned.Below the nner race portion of the member 82 is a threaded port1on89-to;wliich a tubular guide 90 for the inner race is threaded. At thelower end of the guide 90 is a bushing 92' having a sliding fit on thestem 52 at a point adjacent the annular fulcrum 66s0 any deflection ofthe bushing 92 upon sidemovement of the finger 18 will be extremelysmall andiunappreciable at the upper end in the plane of the bearing 84.Thus, it will become apparehtthat the ,member 82 is supported inthe stem32 only for vertical movement to be imparteclthereto by theball78 byboth axial and' -l'ateral movement. of the seat 76. 1

To attach the stem 32to the main valve. body 94, the

f u'pper" end of the.stem 32 is threaded to the plate 96 which iii-turnis piloted upon the valve end plate 198' and, at-

tached to the body 10 by screws 100. Hardened hushmgs 102 and 104 arepressed into a central opening 106 in the plate 98 and shaped to providean, oil chamber 108.

Pin,110.'rides on the top of the member 82 with a closelsliding fitwhich permits very little oil to pass by yetthe pin 110 is freelyslidable in the bushings 102 and .104; At its upper end, the pin 110abuts a metallic washer 112 and acts, through a resilient cushion orpad. 114, preferably of synthetic rubber, upon the push 'rod 116.. Thelower threaded end of the rod, 116 receives a socket 117 which holds.thecushion 114. between the the annular port areas plishedby removingthe threaded cap 142. A plunger 44 against whichithe spring 138abuts atitsupper eiid has a manual push rod 146' which may be depressed to buildup the compression upon the spring 138 should the valve spool 120 becomestuck in its raised position.

The four-way valve construction for selectively directing the hydraulicfiuidto opposite ends of the cylinder 148 attached to thespindlestructure functions in a well known manner. Movable valve spool 120 isprovided with lands 150 which are machined with "great accuracy as towidth, spacing; and diameter. To provide corresponding' accuracy ofconstruction in the fixed ported structureof the valve, the sectionalconstruction of Fig. 4 is stacked withinthemain through bore 152 andcomprises an upper section 154, an intermediate section 156 and a lowersection 158 Between these sections are spacer port rings 160 and 162which are milled to provide radial ports with the surface 168 betweenthe teeth 166 being inclined, This arrangement provides the spacer rings160 and 162 with, maximumstren gth. Also, the 1 rings 160 .and 162 maybe ground on opposite sides to control their thickness with greataccuracy as well as the thickness of 170 between the surface ref-thesections 154, 156 and 158 spaced .by the rings 160 and 162 and regulatedby thelands 150.

It will be understoodth t.the end surface of each section 154, 156 and158 are conveniently groundparallel and the overall length readilyfheldto extreme accuracy. Thus, the structure of Fig. 4 when stacked withinthe bore 152 will have its over, all length accurately held and the portareas 170 will beaccurately located with respect lower endof the rod 116and the washer 112. The lock having an annular flange 124. To expand theupper end er the rod ,116 to lock it to the sleeve .122, the rod .116 isfirst drilled to onedepth by a small drill, then to a lesser depth withalarger drill. The larger holeis then tapped and the end of the rod116'is slotted at 116' at right angles beyond the depth of thesmallfdrill. Thus,

screw 126 may be rotated and advanced to engage the shoulder 116" formedbetween the holes of" difierent diameter. to expand the externallythreaded slotted. end; of the rod 116' into locking engagement with theinternal threads of the sleeve 122. At the upper end the valve spool 120is counterbored at 128'to receivethe flange 124 of the-sleeve 112'. Anannular groove" 1-30' in'the .shoulder 174.

to each other as well as with respect to ,the lands150. Acap172 boltedto the body 94 locatesthe fixed valve structure of Fig. 4 between Thecap142 is threadedinto the cap '172 gasket at 174 and'an O-ring 176 ductedby an appropriate passageway in body 94 to the ports. of section 156and. depending on the direction of movement1oflandsL150 will either flowinto chamber .187 or 189 throughqthe port areas.170. Chambers '187 and189 are. in communication with cylinder connections 188 and. 190,respectively, by means of passageways formed in body .94, not shown, andthe ports of sec fvvhen the rod,116' is held. against. rotation by asuitable .wrenchiengaging the slots, the pointed. end'of' the set tions.154 and 158, will provide communication with the exhaust passageway ofconnection 186 whereby communieatien" of connection188 withthe pressurefluid opens 190 l to the'exhaustand vice versa to move the cylinders 148u in the desired directioncounterbore 128 receives a two-piece lockingring 132.

Iiloted upon the sleeve 122. is aslidable collar. 134 having a radialflange portion '136'to provide a seat for. the spring 138 and a thincylindrical lower end portion 140 of slightly lesser diameter than thelockjring 132 tohold i the same in its groove 130 to lock the sleeve 122to the spool 120.

' trolling valve chatter" p when the widths of the'lands 150 areonly inthe order a of .00 widerthan the .port area 170. as is done whenextremely fine duplication is desired. ,Any tendency for f the valves'eerl'zam vibratepor chatter is overcome by Referring-WOLFE. 6;.thestructure 'is shown for conwhiclif has a tendency to, developmaintaining the'valve chamber full ofoil and metering From .this itshould appear that thespring 13 8 acts downwardly on the valve spool120indirectly through the collar 134 and flange 124 while the rod 116 actsupwardly" 'onthe valve spool 120 through the flange'124 I and the lockring 132. By adjusting the sleeve 122 along: the rod 116, the positionoffthe valve spool 120" relative 't'oits fixed ports may be adjusted."Thismaybeaccomneedle, valve 182. )p g mentbffthevalv'e spoolfiscontrolled 'byrthe' flow l shown in Fig. 61 if depen the valve chamber,

Fig. 3 is showri inplan view with the oil pressure inlet connectionat'184,, the'oilfpressure exhaust connection at "186' and the oi the oilbetween opposite. ends otthe valve chamber between 'paiss'ages 178;"and'.18 0 regulated by the adjustable In this'umanner, the rate of moveofoil past the needle 'valve182.

, Itwill be apparent that the ,oil' check arrangement dentuponmaintaining of oil in Referring to Fig. 7, thecap 172 of pressure;connections leading to opposite ends of the cylinder 148'beingindicatedat 188'and 190.

1 64 defined. between radial teeth 166 the bottom plate 98 and the besealed withinthe chamber] in The intake 6 To-conduct oil from theconnection 184 a horizontal passage 192 opens into the lower endof thevertical threaded hole 194. An inclined passage 196 extends fromadjacent the upper end of the hole 194 into the cen- 'tral opening 198'in the cap 172 which defines the upper portion of the valve chamber. 4 Vr A screw 200 having a gasket 202 beneath its head is threaded into thehole 194 to regulate the flow of oil in the passages 192 and 196; theoil under pressure seeping along the spiral clearance between thethreads of the hole 194 and the threads of the screw 200, the clearancebeing regulated by the diameter of the threads of the screw 200.

The oil in the valve chamber which enters through the passage 196 isexhausted through the passage 204 into the chamber 206 and out thepassage 208 into the exhaust connection 186. The chamber 206 is in theform of a hole threaded at its upper end to receive the screw 210 whichseals the upper end of the chamber 206 and acts as an abutment for thespring 212 which holds the ball valve 214 to its seat. The pressure ofthe spring 42 controls the oil pressure within the valve chamber.

As more clearly shown in Figs. 2 and 3 a collar 216 embraces the lowerend 58 of the stem holder'56 and is removably aflixed thereto in anysuitable manner as, for example, by means of a pin 218. A manual knob220 is provided for rotating the collar 216 and the stem holder 56 as aunit relative to the stem housing 32. Such rotation will result in thestem holder 56 being raised or lowered depending upon the direction ofrotation due to its threaded connection at 222 with the lower end 58 andthe housing 32. To limit the amount of rotation of the collar 216 to apartial revolution, an armate recess 224 is machined from the end threadof the housing 32 to provide shoulders 226 at the ends of the recess 224with which a pin 228 carried upon the collar 216 will engage.

It will be appreciated that when the collar 216 is rotated in onedirection the seat portion 68 acts upon the edge 70 to lift the stem 52and move the valve spool 120 into its up position to raise the tool 16.When the operator Wishes to lower the tool 16 into engagement with thework 23 rotation of the collar 216 in the opposite direction will enablethe operator to cautiously approach the work with the tool. Thus, thecollar 216 provides a conveniently located control means for raising andlowering the tool 16 relative to the work. When the tracer finger 18 isto engage and follow the template 20, the collar 216 will be rotated toremove the seat 68 from the edge 70 thus transferring the support of thetracer stem to the tracer finger 18.

I claim:

1. In a hydraulic duplicator attachment for machine tools and the like,a fluid control valve, means for actuating said valve comprising atracer finger, an elongated axially movable stem carrying said finger,fixed port struc ture regulated by said valve, a housing for said stem,a seat carried byrsaid housing at its lower end and having a centralaperture through which said stem extends, an annular radially extendingshoulder on said stem and engageable with said seat to support saidstem, said stem housing having a reduced annular portion directlyadjacent and above said seat defining a narrow closely fitted annularfulcrum for said stem and defining the pivotal plane of said stem, saidstem having clearance with said housing above and below said plane forlimited pivotal and axial action in all directions about said fulcrum.

2. In a hydraulic duplicator attachment for machine tools and the like,a fluid control valve, means for actuating said valve comprisinga tracerfinger, an elongated stern carrying said finger, a tubular housing forsaid stem, a narrow annular fulcrum for said stem located at the lowerend of said housing which consists of a reduced annular portion withwhich said stem has a closely fitted axially slidable association, and aconnection between '6 the upper end of said stem and said valve'fortransferring axial movement to said valve upon pivotal and axialmovement of said stem.

3. In a hydraulic duplicator attachment for machine tools and the likeas defined in claim 2 wherein said con; nection comprises a balldisposed between a pair of annular seats.

4. In a hydraulic duplicator attachment for machine tools and the likeas defined in claim 2 wherein said stem has an annular shoulder and saidhousing is provided With an annular seat directly adjacent said annularfulcrum upon which said shoulder is adapted to be supported.

5. In a hydraulic duplicator attachment for machine tools and the likeas defined in claim 2 wherein said stemhas an annular shoulder and saidhousing is provided with an annular seat directly adjacent said annularfulcrum upon which said shoulder is adapted to be supported, thatportion of said housing carrying said seat and fulcrum bsling axiallyadjustable to raise said stem and actuate said v ve.

6. In a hydraulic duplicator attachment for machine tools and the like,a lapped valve mechanism having opposite end portions for selectivelycontrolling the flow of hydraulic 'fluid to opposite ends of anactuating cylinder upon minute movement of said valve structure, springmeans for urging said valve structure in one direction, tracer mechanismfor urging said valve structure in the opposite direction, and ahydraulic dampener for said valve structure to prevent chatter thereofcomprising a closed hydraulic fluid circuit extending between theopposite ends of said valve structure with the latter functioning as apiston in said circuit and an adjustable restriction in said circuit forregulating the flow of hydraulic fluid therein.

7. In a hydraulic duplicator attachment for machine tools and the like,a lapped valve structure having opposite end portions for the regulationof the flow of fluid to opposite ends of a cylinder upon minute movementof said valve structure, spring means for urging said valve structure inone direction, tracer mechanismVfor urging said valve in an oppositedirection, and aclosed hydraulic circuit for obviating chatter of saidvalve structure under the influence of said tracer mechanism connectingthe opposite ends of the cylinder in which said valve functions as apiston and an adjustable restriction in said closed circuit forregulating the transfer of hydraulic fluid from one portion to the otherthereof.

8. .In a hydraulic duplicator attachment for machine tools, movablevalve structure for regulating the direction of fluid flow to and from ahydraulic actuator, a

tracer finger, a tracer stem structure connected between said finger andsaid valve structure for imparting the movement of said finger to saidvalve structure, an externally threaded stem housing concentricallyencompassing said stem structure, mounting structure for said stemhousing including a sleeve in which said stem housing is verticallyslidable, and an internally threaded adjustment ring rotatably supportedby said sleeve with which said stem housing is threaded for verticaladjustment of said stem housing in said sleeve upon rotation of saidring.

9. In a hydraulic duplicator attachment for machine tools, valvestructure comprising a movable valve spool, a sectional sleeve valve inwhich said spool is reciprocated, said sleeve valve being in the form ofa pair of ported sections separated by a relatively thin spacer section,said ported sections having end walls spaced by said spacer portion,said spacer portion being in the form of a ring having radial teeth onthe inner circumference thereof with portions between said teeth beinginclined to' ment of said tracer finger to said spool va'1v,e,1and

man mu:

Itracer fingen-andsaid.spo0l,va1ve for impartingih eforce transmitting;cushion memberimpossd betwcenpqaidV stem and saidspool valve. l H A 5 l1 1 11 .L

. ,51 aL I Qm- V, UNITED STAT? PATENTS, -.2; 2 ;8.4 1 .52 531,719! R llfi-g-l-qrr Ap 6 191 0 2;6'18,2 4 R m 1-, -1 1252

